bcachefs: Have btree_iter_next_node() use btree_iter_set_search_pos()

btree node iterators need to obey the regular btree node invarionts
w.r.t. iter->real_pos; once they do, bch2_btree_iter_traverse will have
less that it needs to check.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index d6ef08b27858c268997216f5432ca918df8291c8..572e553d55b185547314adfe76ad478daa9f84eb 100644 (file)
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -16,6 +16,8 @@
 
 #include <linux/prefetch.h>
 
+static void btree_iter_set_search_pos(struct btree_iter *, struct bpos);
+
 static inline bool is_btree_node(struct btree_iter *iter, unsigned l)
 {
        return l < BTREE_MAX_DEPTH &&
@@ -1144,11 +1146,6 @@ err:
        return ret;
 }
 
-static void btree_iter_up(struct btree_iter *iter)
-{
-       btree_node_unlock(iter, iter->level++);
-}
-
 static int btree_iter_traverse_one(struct btree_iter *, unsigned long);
 
 static int __btree_iter_traverse_all(struct btree_trans *trans, int ret)
@@ -1400,11 +1397,11 @@ struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
 
        bch2_trans_cond_resched(iter->trans);
 
-       btree_iter_up(iter);
-
-       if (!bch2_btree_node_relock(iter, iter->level))
-               btree_iter_set_dirty(iter, BTREE_ITER_NEED_RELOCK);
+       btree_node_unlock(iter, iter->level);
+       iter->l[iter->level].b = BTREE_ITER_NO_NODE_UP;
+       iter->level++;
 
+       btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
        ret = bch2_btree_iter_traverse(iter);
        if (ret)
                return NULL;
@@ -1419,20 +1416,15 @@ struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
                 * Haven't gotten to the end of the parent node: go back down to
                 * the next child node
                 */
+               btree_iter_set_search_pos(iter, bkey_successor(iter->pos));
 
-               /*
-                * We don't really want to be unlocking here except we can't
-                * directly tell btree_iter_traverse() "traverse to this level"
-                * except by setting iter->level, so we have to unlock so we
-                * don't screw up our lock invariants:
-                */
-               if (btree_node_read_locked(iter, iter->level))
-                       btree_node_unlock(iter, iter->level);
-
-               iter->pos = iter->real_pos = bkey_successor(iter->pos);
-               iter->level     = iter->min_depth;
+               /* Unlock to avoid screwing up our lock invariants: */
+               btree_node_unlock(iter, iter->level);
 
+               iter->level = iter->min_depth;
                btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
+               bch2_btree_iter_verify(iter);
+
                ret = bch2_btree_iter_traverse(iter);
                if (ret)
                        return NULL;